1. Field of the Invention
This invention relates to composite fabric materials made of reinforcing fibers such as carbon fibers and a matrix, and a manufacturing process thereof.
2. Description of the Related Art
Composite fabric materials, or fiber-reinforced plastic materials, have been widely used as component materials of aircrafts, boats, sporting goods and other items. In composite fabric materials made of fibers such as carbon fibers, fiber bundles (yarns, also referred to as tows when the fibers are unidirectional) are typically held together by an adhesive material. One existing method of producing such a material uses a “prepreg” formed by impregnating carbon fiber bundles with an epoxy resin composition or other adhesive material. One example where such a method is used is described in U.S. Pat. No. 6,399,199, entitled “Prepreg and carbon fiber reinforced composite materials”. Another existing method uses yarns that are stitched together with a thread such as cloth, polyester or s-glass thread. One example of a stitched laminate is described in U.S. Pat. No. 6,599,610, entitled “Multiaxially stitched base material for reinforcing and fiber reinforced plastic, and method for preparing them”. Another example of a fiber reinforced material and method of making such is described in U.S. Pat. No. 6,565,944, entitled “Resin composition, a fiber reinforced material having a partially impregnated resin and composites made therefrom”. This method involves stitching a stack of partially impregnated preforms together prior to curing to form a fiber-reinforced resin composite upon curing. One disadvantage of composite fabric materials made by the conventional methods is that they tend to be stiff and difficult to work with and thus unsuitable for certain applications.